Slowpoke Productions
is the creator of the Randomly Oscillating Magnetic Pendulum (ROMP).

The ROMP is an addictive
desktop toy that combines magnetic forces, gravity, and pendulum motion
to create an endless variety of chaotic motions shaped by the magnetic
landscapes you create.

You choose the arrangement
of magnets on the ROMP's base to create fields through which the pendulum
must swing. The complexity of the fields is limited only by your imagination.

Then simply let the
pendulum loose and watch it dart and dodge through the fields!

Originally
crafted in the early 1990's from birdcage perches, shishkabob skewers, and the shell of a
PC, the ROMP found its first admirers in the physics department at Bellevue Community College. The name was coined by the inventor's spouse for a college writing assignment in which the student had to author an explanation for a difficult-to-explain object.

After some design improvements, a handmade version was offered for retail sale in Pacific NW science and nature stores in 1993 and developed an eager and devoted following.

The ROMP was later manufactured
and sold under exclusive license through Hog
Wild Toys. Hog Wild production has ended and no further stock is known to exist. A handful of original hand-made units are available directly from Slowpoke Productions (natural wood and textured gray powder-coated base).

If you have to take
it with you, here's how you can make a portable
ROMP out of an Altoids tin.

And there are plenty of videos of the ROMP, similar mechanisms, and computer simulations with explanations and musings on YouTube.

And no, there is no perpetual motion or anything of the sort at work here. The system is simply very efficient with very little loss in air friction or the strand of nylon used for the pivot. The pendulum is intentionally rigid which further reduces mechanical friction losses. This all makes the exchange of energy between gravitational potential energy, magnetic potential energy, and kinetic energy very efficient. In addition, we are accustomed to thinking of the total energy in a traditional pendulum as being related to how high the pendulum is lifted above its lowest point the swing. However, in a ROMP it's related to the lowest point in one of the attracting magnetic "wells" and given the strength of the ROMP's magnets (especially if stacked) that well can be quite deep and accelerate the pendulum to high peak speeds. We think it's the introduction of the added dimension of magnetically-induced and unexpected motions and the greater than expected total stored energy in the raised pendulum that make the ROMP's actions so seemingly energetic.

(If you're looking for the vintage Macintosh gear we have for sale, look here.)